Background: Second-generation and third-generation oral contraceptives containing 30 mcg or more of ethinylestradiol (EE) decrease insulin sensitivity (SI). In this study, we investigated whether SI is decreased by contraceptives containing lower doses EE or by progestins with antiandrogenic properties.
Study design: Twenty-eight young healthy women were randomly allocated to receive 20 mcg of EE and 150 mcg of desogestrel (DSG) (n=14) or 30 mcg of EE and 2 mg of chlormadinone acetate (CMA) (n=14) for 6 months. SI and glucose utilization independent of insulin (Sg) were investigated by the minimal model method. Lipid modifications were also analyzed.
Results: SI decreased with EE/DSG (7.09+/-1.4 vs. 4.30+/-0.91; p=.04; n=12), but not with EE/CMA (5.79+/-0.93 vs. 6.79+/-1.1; p=.48; n=12). SI modifications observed in the two groups were significantly different (-2.79+/-1.15 vs. 1.0+/-1.38; p=.05). Sg did not vary with either treatment. The response of C-peptide to glucose increased, but significantly so only with EE/CMA (p=.01). The C-peptide/insulin response increased with both EE/DSG (p=.05) and EE/CMA (p=.04). High-density lipoprotein (HDL) cholesterol (p=.02) and triglycerides (p=.02 and p=.01) increased in both groups, but HDL/low-density lipoprotein cholesterol (p=.02), apoprotein A1 (Apo-A1) (p=.04) and Apo-A1/apoprotein B (p=.048) increased significantly only with EE/CMA.
Conclusions: The present study confirms that DSG, even when associated with low EE dose, decreases SI. By contrast, EE/CMA does not deteriorate SI and induces a favorable lipid profile.